Terrestra Instuderingsfrågor Flashcards
In which climatic zone(s) are the largest soil carbon stocks?
In the tropics and at high latitudes.
Describe roughly which parts of the planet are covered by deserts!
North Africa, mid Asia, Australia, west USA, east South America.
What environmental parameter is the main driver of desert formation (as opposed to other vegetation types)?
Water (precipitation, runoff, etc.). Wet, warm.
Describe briefly how global warming is expected to affect greenhouse gas emissions from permafrost soils!
Global warming causes the atmospheric temperature to rise. The rise in temperature leads to thaw of permafrost, which causes degradation of organic matter to carbon dioxide and methane. The concentrations of carbon dioxide and methane in the atmosphere leads to an even higher temperature increase, thawing even more permafrost.
Define deforestation, afforestation and reforestation!
Deforestation: The removal of forest with conversion of land to non-forest use.
Afforestation: Establishment of forest where there was no forest before.
Reforestation: Natural or intentional restocking of depleted forests.
How does deforestation impact the global carbon cycle?
Deforestation is a source of carbon to the atmosphere, as well as reducing the carbon dioxide uptake from the atmosphere.
What is albedo?
The fraction of light reflected by a surface. White surfaces reflect much light, giving a cooling effect, albedo = 1. Black surfaces reflects little light, giving a warming effect, albedo = 0.
Give three examples of land use change!
Conversion of forest to cropland.
Conversion of forest to pastures.
Drainage of wetlands and conversion to cropland.
Intensification of agriculture.
Spread of urban areas into agricultural land.
Abandonment of pastures.
Reforestation of pastures.
CO2 emissions from land respiration vs fossil fuels: Which one is larger?
Carbon dioxide emissions from land respiration is much larger than the emissions from fossil fuels, over 10 times larger. The emissions from fossil fuels still have a large effect on the climate.
What is ecosystem services? Give three examples!
Ecosystem services are benefits that society derives from ecosystems.
A few examples of ecosystem services are food, pollination, water, photosynthesis, recreation.
What is the difference between primary and secondary succession?
Succession is the process by which the structure of a biological community changes over time.
Primary succession occurs after severe disturbances that remove or burry most products of ecosystem processes, for example after lava flows, glacier retreat, and on new sand dunes.
Secondary succession occurs after moderate disturbances, and begins on soils that developed beneath vegetation, for example after fires.
Primary succession occurs after more severe disturbances than secondary succession.
Name the main factors determining soil formation!
Time, climate, organisms, topography, parent rock.
Describe briefly how natural factors, land use change and climate change influence fires!
Natural factors such as vegetation can influence fires. Savannahs are more prone to fires than rainforests.
Land use change can influence fires, for instance by planting certain plants that might be more prone to fires than the vegetation that dominated before.
Climate change can influence fires, for instance by changing the vegetation, heat waves, droughts, etc.
